Summary: Successful therapy for Gaucher's disease depends upon a comprehensive clinical and basic scientific knowledge of the disorder. Patients have been extensively studied and complications identified. Research on glucocerebrosidase addresses the biochemistry, cell biology,and molecular genetics of the enzyme. A pharmacodynamic assessment of mannose-terminated human placental glucocerebrosidase has been completed. Extraordinarily gratifying results have been obtained with enzyme replacement therapy in patients with Gaucher's disease.